Heterodera medicaginis
Kirjanova & Krall, 1971
Photo Gallery- Kansas Alfalfa

Observations on three fresh specimens: lemon-shaped with well developed subcrystalline layer covering the whole body including the neck.  Sometimes a reddish-brown cement at the neck region.   Head consisting of a labial plate and two annules.  Spear well developed, 27-28 um long.  Spear knobs sightly concave anteriorly.  Dorsal oesophageal gland orifice 5-6 um behind the spear base.  Median bulb well developed, rounded with distinct valve in the middle.  Excretory pore about level of the median bulb.  Cuticle with zig-zag pattern and distinct punctation.

Measurements (n = 10). Length (excluding neck and vulval cone): 635 um (568-728 um); width: 466 um (364-570 um); vulval cone: 79.6 um (70-84 um); depth of underbridge: 71.6 um (64-80 um). Lemon-shaped with distinct neck and vulval cone.  Neck usually twisted.  Colour changes from creamy to tan into brown during maturation.  Thick subcrystalline layer which sticks firmly to the cyst.  Cuticle with zig-zag pattern and scattered punctation.  Sometimes small egg sac present without any content.
     Cyst cone ambifenestrate.  Fenestra measurements (n = 15).  Length: 46.6 um (39-55um); width: 34.1 um (30-40 um); vulval slit: 44.7 um (39-55 um).  Vulval bridge 5-10 um wide; underbridge (n = 9): 40-60 um long and 6-10 um wide.  Bullae present, well developed.

Second-stage juveniles
Measurements (n = 100).  L: 462 um (417-512 um); a: 24.4 (22.0-27.6); c: 8.8 (7.5-11.4); spear: 25 um (24-26 um); head-end to median bulb valve: 72 um (62-82 um); head-end to excretory pore: 19 um (18-20 um); anal body width: 13 um (11-15 um).
     Body cylindrical, gently curved with a conical tail.  Lateral field with four incisures, not aerolated.  Lip region rounded, offset with two head annules.  Spear knobs well developed, rounded posteriorly, concave anteriorly.  Dorsal oesophageal gland opening 5-6 um behind the spear knobs.  Median oesophageal bulb valve plates prominent.  Excretory pore located 93-120 um from the anterior end.  Heminzonid two body-annules wide, just in front of the excretory pore.  Oesophageal-intestine junction obscure.  Oesophageal gland lobe elongated, extending about 40% of the body-length and filling most often half of the body cavity.  Dorsal gland nucleus prominent, sub-ventral gland nuclei more posterior and smaller.  Genital primordium with two nuclei located at 51-60% of the body length.  Tail 51.8 um (41-60 um) long, with rounded terminus.  Hyaline terminal section 28.5 um (22-33 um) long and on the average 1.1 times the spear length.  Phasmids very small, located at the anterior third of the tail.

Measurements (n = 30).  Length: 102.6 um (98-115 um); width: 46.9 um (44-51 um); L/B 2.1 (1.9-2.4).

Measurements (n = 25).  L: 1322 um (1140-1470 um); a: 58.7 (49-69); width at excretory pore: 21.6 um (21-26 um); spear 28.8 um (28-30 um); head-end to median bulb valve: 97.7 um (83-116 um); head-tip to excretory pore: 157.7 um (131-187 um); anal body width: 15.5 um (14-18 um).
Cuticle annulated.  Lateral field with four incisures, appears not aerolated.  Lip region rounded, offset with four or five annules.  Spear knobs rounded.  Dorsal oesophageal gland opening 5 um posterior to spear knobs.  Median oesophageal bulb ellipsoid; valve plates prominent, situated in the posterior third part of the bulb.  Excretory pore 131-187 um from anterior end.  Hemizonid about 2 annules wide, 5-13 annules anterior to excretory pore.
     Hemizonion not observed.  Oesophageal-intestine junction usually about level of excretory pore.  Oesophageal gland lobes filling nearly the whole body cavity.  Nucleus of the dorsal gland bigger than the two subventral nuclei.  Testis one.  Spicules curved, 32-39 um long (N = 4) with bidentate tips.  Cuticle protruding around the cloacal aperture.  Gubernaculum a simple rod, 10-11 um long.  Cuticle of tail tip ventrally thickened, forming a small cap.  Tail usually twisted.  Phasmids not observed.

(Description- Gerber and Maas, 1982)

DNA Sequences Obtained
Specimen: Collected:
KS Alfalfa-3 Lakin, Kansas
KS Alfalfa-1 Lakin, Kansas